Cellulose/Poly(Vinyl Alcohol)/Graphene Composite Photothermal Aerogel Membrane for Solar-driven Seawater Desalination

Photothermal conversion at the water-air interface has been considered a promising route for steam generation, distillation and desalination. Due to the strong lattice vibration, high conductivity and substantial thermal stability, carbon materials, such as carbon nanotubes, graphene oxide and graphene, are considered promising photothermal materials for solar-driven water evaporation. However, most of the interfacial photothermal evaporators based on graphene are hydrophobic and often require complicated systems with multiple components. Herein, a 3D porous Cellulose/Poly(vinyl alcohol)/Graphene photothermal aerogel membrane that has distinctive properties, i.e., creditable hydrophilicity, broadband light absorbance and substantial thermal stability is fabricated by freeze-drying method. When the graphene content is 15 wt%, the light absorbance of the hybrid aerogel membrane is improved remarkably. Under the simulated solar irradiation (1 kW m- 2), the surface temperature of the wet aerogel is 48.6 degrees C, and the evaporation rate reaches 1.17 kg m- 2 h- 1, and the evaporation efficiency is 71.12%, benefit from the excellent photothermal conversion of graphene and the porous structure of the aerogel. Such all-in-one solar distillation and self-containing evaporation mode indicate the great potential of the cellulose aerogel membrane for practical solar-driven seawater desalination.